I use the API and range charge for my data collection. Your statement notwithstanding, I see absolutely no variation (to the hundredth of a kWh) from one day to the next, until the days when degradation occurs. I never see any variance in an upwards direction. For my last readings, charging completed at 257.38 for two days in a row, down from 272.80. Unsurprisingly, Tesla's techs' reading of my logs yield the same numbers as my data collection.
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I use the API and range charge for my data collection. Your statement notwithstanding, I see absolutely no variation (to the hundredth of a kWh) from one day to the next, until the days when degradation occurs. I never see any variance in an upwards direction. For my last readings, charging completed at 257.38 for two days in a row, down from 272.80. Unsurprisingly, Tesla's techs' reading of my logs yield the same numbers as my data collection.
Curious. Is there a difference in lowering the AMPs to say 12 vs using a 110V plug?
islandbayy
Active Member
Well, at 4,300 miles last night, I ran my battery down to 0 rated range (purposely, as my YouTube viewers wanted to see what happens when you get low).
Since I got my car, my Standard charge has never gone over 190 miles. Well, today, after charging at 40 amps all night to replenish my battery for a long drive today, I came out to my car, about 4 hours AFTER it finished charging.
Low and behold, my Rated Range, even after 4 hours of Vampire losses, was 192!!!!!!!!!!!!!!!!!
Seems the car decided to balance the battery pack last night. All I can say is, awesomeness! My range is GOING UP over time instead of down! WOOO HOOOO!
Since I got my car, my Standard charge has never gone over 190 miles. Well, today, after charging at 40 amps all night to replenish my battery for a long drive today, I came out to my car, about 4 hours AFTER it finished charging.
Low and behold, my Rated Range, even after 4 hours of Vampire losses, was 192!!!!!!!!!!!!!!!!!
Seems the car decided to balance the battery pack last night. All I can say is, awesomeness! My range is GOING UP over time instead of down! WOOO HOOOO!
While what you are doing is more accurate, correlating rated range(especially a loss that small) to capacity loss is probably not too accurate. While Tesla let's the techs download and read logs, they are mostly part swappers, and every single complex issue(all battery issues) are dealt with by engineering. Getting a concrete answer from Tesla about battery performance and functionality is about impossible. A good example of this is the battery balancing issue, and the multiple answers and silence.
FredTMC
Model S VIN #4925
I started this battery balance exercise by doing a std charge. I had 182 mi rated range after a standard charge on v4.4 using nema 14-50 @ 40a. In other words, in was a completely normal standard charge.
Then, I immediately began a "range" charge using 110v outlet (I unplugged nema and switched to 110v). During the range charge, it took many hours to get to 199mi from 182 starting point. It was charging at 3mi per hour. Yes, I was completely shocked to see 199 because previously I've only ever seen 197.
Once the range reached 199mi, the car continued to charge for over an hour and the charge port ring was solid green during this time. I concluded the battery was balancing during this time.
Once the range charge was done, I immediately took the car for a drive. Upon returning home, I had 172 rated range. Now it was time for the real test. I set the car to do a standard charge and plugged in using nema. To my amazement the car finished at 185mi. I'll do another standard charge today and see if I still get 185 instead of 182. I assume so.
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I assume that works also. Yes, I'd rather use this method to balance. Nothing to unplug from wall. However, for this first experiment, I figured a real 110v outlet was the best approach.
djp
Model 3 Performance
Wondering... when does the S balance the batteries if you only do a "standard" charge and go with 40AMPs? Big mystery
I'm starting to question the collective wisdom that the Roadster never balances below a Standard charge.
Last night I charged to 54% (about 176km). The highest brick voltage was 3.84V and lowest brick voltage was 3.81V. After sitting overnight the SOC dropped to 51% (about 164km). The highest brick voltage dropped to 3.82V but the lowest brick voltage stayed at 3.81V.
The car seems to have bled off the highest bricks, even at 54% SOC. Also my balancing matrix has always been zeros despite regularly doing partial charges.
djp
Model 3 Performance
On the Model S, nothing. :smile:
An unbalanced pack might show lower capacity but it's not actually degraded, rebalancing it will bring the miles back.
I'd avoid doing regular Range charges at 120V just to get the displayed miles up. Li-Ion batteries don't like to be at high SOC and high temperatures. The BMS aggressively cools the pack when doing a Range charge at 240V, but at 120V there isn't enough power to run the cooling so it lets the battery get hotter. This is the worst possible combination and probably not worth it just to get a higher number on your display.
I'd do a Range charge whenever you need one for a road trip and let the battery balance naturally. From what I can tell the Roadster continuously balances the pack and the Model S probably does the same.
Todd Burch
14-Year Member
I agree with djp. Charging really slowly to a full range charge probably does more harm than good. And remember, you're not improving the capacity of your batteries--just the apparent capacity by having balanced cells. Overall, you're probably accelerating degredation by doing this.
Personally, I'm going to wait until we have clear official word from Tesla on pack balancing before doing anything. It's not like the few miles + or - of range here and there really makes a difference. You can make up for that just by driving more efficiently for a little bit if you're going to go near the limits of your pack.
Since Tesla hasn't said a word about this, I suspect the pack will automatically balance itself continuously over time--we just don't know when. But either way, slow range charges to get a few miles higher on the display is probably counterproductive.
Personally, I'm going to wait until we have clear official word from Tesla on pack balancing before doing anything. It's not like the few miles + or - of range here and there really makes a difference. You can make up for that just by driving more efficiently for a little bit if you're going to go near the limits of your pack.
Since Tesla hasn't said a word about this, I suspect the pack will automatically balance itself continuously over time--we just don't know when. But either way, slow range charges to get a few miles higher on the display is probably counterproductive.
It depends on who at Tesla you ask! The consensus is that for roadsters you charge the car in range mode, and let it sit plugged in for a few hours after the charge completes. Depending on how out of balance the pack is, it might require this to be done a few times. 120v charging seems to balance the pack a bit quicker.What does Tesla say about balancing batteries to "Restore" the loss of rated range on a charge?
I'm relatively new to the forums, thanks in advance for sharing your institutional knowledge
As for the model S, the same might be true(too early to tell), but I have found that charging on 120V to a full standard charge(firmware 4.4 and earlier), helps to balance the pack.
To echo what everyone has been saying here, I've had my normal charge range reduced by 12 miles in the last 2 weeks. The car stops charging now once it hits 230miles, it used to stop at 242 or 243. Any idea what this is related to? I don't think it's mileage related, I only have 4300 miles on the car. This also happened rather fast so I don't think it is battery wear related. Maybe it's the heat we have been having in Chicago, it's been 100 almost every day for the past week. I'm still running 4.4 btw
My theory is that you ninja-updated to 4.5 (maybe during service?). Check your about box. Or maybe you updated the phone app and set it to 90% directly or indirectly that way.
Is there an update to the iPhone app that would allow you to adjust charge limits? Mine still shows standard and max range as the only options.
Checked the status box today, still running 4.4, this is weird. Anyone else have seen something like this?
I just did my first 90% charge on 4.5, and its 239 rated miles right after is stopped charging. On 4.4, my car would charge to 242 rated miles for a standard charge most of the time. I baby my battery, and live in a climate with 85 F for the highs. Just thought I would share a reference point of going from 4.4 to 4.5.
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